The problem of Western impact on non-Western societies isn't IMO primarily one of the violence that undoubtedly accompanied it, it's more to do with the uninvited force of this modernity and the subsequent sense of alienation that followed. In terms of the Islamic world, consider this - prior to the 19th c., a Muslim's sense of his place in the world, as a Muslim, was defined by a range of different beliefs and institutions - belief in God and his final message, belief in the unity (not necessarily political) and primacy on earth of the umma who accepted it, and subsequently the belief in the inevitable triumph of Muslim arms; institutions such as the caliphate, which represented in theory the political unity of the umma, the shari'ah, which ensured a certain measure of legal conformity across a politically divided umma, and the Sufi orders which provided transnational/continental networks for merchants, scholars and travelers to tap in to from Spain to India.
The modernity which arrived with the West undermined pretty much every single one of these - belief in God and his final message by the introduction of Western science; the unity of the umma by the idea of nationalism; the political and military supremacy of the Muslims and the primacy of the caliphate by the triumph of Western arms; the shari'ah by the introduction of Western legal codes; and the Sufi networks by the imposition of modern borders and alternative secular forms of transnational solidarity. So to be consciously Muslim today is in many ways to be confronted with an assault on your sense of place in the world which draws many to the simple and reassuring claims of Islamism in its various forms.